Process for manufacturing lubricating oil

ABSTRACT

A process for manufacturing a lubricating oil comprising a first step of passing a deasphalted crude oil distillation residue containing by weight at least 85 percent of constituents boiling above 500*C and at least 75 percent of consituents boiling above 525*C, with hydrogen over a hydrogenating catalyst with a cracking carrier at 330*-450*C, at a hydrogen partial pressure of 80-240 kg/cm2, at such a flow rate that the hydrocarbons in the resulting product boiling below 525*C amount to 70-95 percent of the initial weight of such hydrocarbons, separating the products boiling below 525*C, and recovering a first lubricating oil fraction of high V.I. and a second step of passing at least a portion of the products boiling above 525*C over a similar catalyst, at the same temperature and pressure ranges of the first step, at such a flow rate that the major part of the first zone heavy products are converted to products boiling below 525*C and separating therefrom, by distillation, a second lubricating oil fraction.

United States Patent Billon et al.

[4 1 Feb. 19, 1974 [54] PROCESS FOR MANUFACTURING LUBRICATING OIL [75] Inventors: Alain Billon, Lyon; Michel Derrien,

Rueil-Malmaison, both of France [73] Assignee: lnstitnt Francais Du Petrole, Des

Carburants et Lubrifiants, Rueil-Malmaison, France [22] Filed: Apr. 6, 1972 [21] Appl. N0.: 241,690

[] Foreign Application Priority Data Apr. 7, 1971 France 7l.l24l6 [52] US. Cl 208/59, 208/18, 252/455 R, 252/465 [51] Int. Cl C10g 13/06, ClOg 37/10 [58] Field of Search 208/59 [56] References Cited UNITED STATES PATENTS 3,494,854 2/1970 Gallagher et al. 208/59 3,560,370 ,2/197l Billon et al. 208/1 ll 3,463,724 8/1969 Langlois et al. 208/98 3,493,493 3/1970 Henke et al. 208/264 3,242,068 3/1966 Paterson 208/111 3,365,390 1/1968 Egan et al 208/60 3 5 u f 12 W 8 9 El g 29 34 I 10 3,684,695 8/1972 Neel et al. 208/110 Primary ExaminerDelbert E. Gantz Assistant ExaminerG. E. Schmitkons Attorney, Agent, or FirmMillen, Raptes & White 5 7] ABSTRACT A process for manufacturing a lubricating oil comprising a first step of passing a deasphalted crude oil distillation residue containing by weight at least 85 percent of constituents boiling above 500C and at least percent of consituents boiling above 525C, with hydrogen over a hydrogenating catalyst with a cracking carrier at 330-450C, at a hydrogen partial pressure of -240 kg/cm at such a flow rate that the hydrocarbons in the resulting product boiling below 525C amount to 70-95 percent of the initial weight of such hydrocarbons, separating the products boiling below 525C, and recovering a first lubricating oil fraction of high V.l. and a second step of passing at least a portion of the products boiling above 525C over a similar catalyst, at the same temperature and pressure ranges of the first step, at such a flow rate that the major part of the first zone heavy products are converted to products boiling below 525C and separating therefrom, by distillation, a second lubricating oil fraction.

9 Claims, 1 Drawing Figure PROCESS FOR MANUFACTURING LUBRICATING OIL This invention concerns an improved process for manufacturing lubricating oils from vacuum deasphalted residues which may, in some cases, contain a minor proportion of vacuum distillates.

It provides, more particularly, oils exhibiting high viscosimetric properties and a satisfactory content of hetero-atoms (particularly sulphur and nitrogenlwith moderate manufacturing costs and a relatively narrow distillation range.

This process consists in performing a hydrotreatment in two stages, under the conditions stated below, of a charge consisting essentially of a deasphalted vacuum distillation residue.

The process for manufacturing the lubricating oil is remarkable in that it comprises passing a deasphalted distillation residue of crude oil containing at least 85 percent by weight of constituents boiling above 500C and at least 75 percent by weight of constituents boiling above 525C, together with additional hydrogen,

through a first catalytic zone containing a hydrogenating element and a cracking carrier, at a temperature of from 330 to 450C and a hydrogen partial pressure of from 80 to 240 kg/cm with such a flow rate that, in the resulting product, the weight of hydrocarbons boiling below 525C amounts to from 70 to 95 percent of the initial weight of such hydrocarbons, separating the relatively light products boiling below 525C, and recovering a first lubricating oil fraction of high V.I. passing at least a portion of relatively heavy products, boiling above 525C, together with hydrogen, through a sec ond catalytic zone containing a hydrogenating element and a cracking carrier, at a temperature of from 330 to 450C and a hydrogen partial pressure of from 80 to 240 kg/cm with such a flow rate that at least the major part of said relatively heavy products is converted to products of said first zone boiling below 525C and distilling the resulting products for separating a second lubricating oil fraction.

If so desired, the treatment of the second step can be performed only on heavy products having an initial boiling point substantially higher than 525C, for example 570C or more. v

Preferably, at the end of the first step, the hydrocarbons boiling below 525C will amount to from 85 to 92 percent by weight of the initial hydrocarbons. It is essential, according to the invention, to comply with the limits of 70 to 95 percent, for the proportion of products boiling below 525C at the end of the first step. As a matter of fact, higher values will result in a quick deactivation of the catalyst; for lower values, the resultin oil will have a low viscosity index.

Unless otherwise indicated, all boiling points given herein are for a pressure of 1 atmosphere absolute.

The process will now be described with reference to the accompanying drawing which shows byway of example, an overall diagram of a unit operated according to the process of the invention.

Through line 1 is fed a charge formed of a preliminarily deasphalted vacuum distillation residue of a raw petroleum or of a mixture of such a residue with a vacuum distillate. a

The deasphalting may be achieved according to any known technique for example, by treatment with of lower paraffinic hydrocarbons, such as propane, butane or a mixture of propane and butane.

This charge is preferably so selected as to have the following characteristics:

initial boiling point higher than 300C, at least percent of the constituents of the charge having a boiling point higher than 500C and at least 75 percent of said constituents having a boiling point higher than 525C;

a viscosity at 989 C in the range of from 5 to cst, preferably from 5 to 50 est;

a viscosity index from 0 to 100;

the following maximum contents:

a. asphaltenes: 0.3 by weight b. nitrogen: 0.3 by weight 0. Conradson carbon: 5 by weight The charge preliminarily admixed with fresh hydrogen and conveyed through line 1 is heated in the oven 2 and then conveyed through line 3 to the first hydrotreatment reactor 4. This reactor is also fed with a gas rich in molecular hydrogen introduced through line 5. Of course, hydrogen may be introduced before or after the passage of the charge through the oven 2. In reactor 4, comprising one or more catalytic beds, there is achieved the hydrogenation of the unsaturated compounds of the charge (and particularly of the alkyl aromatic compounds) as well as at least a partial cracking of the naphthenic compounds present in the charge or obtained by hydrogenating said charge in reactor 4.

The operating conditions of reactor 4 are preferably as follows:

L.H.S.V. from 0.1 to 2 liters of liquid charge per liter of catalyst and per hour;

ratio of the flow rate of pure gaseous hydrogen to the flowrate of liquid charge in the range of from 500 to 5,000 liters per liter;

hydrogenating gas (line 5): hydrogen purity higher conveyed through line 13 to an oven 14 and then through line 15 to a first distillation column 16 operated under a pressure close to the atmospheric.

There is thus separated several fractions, for example light hydrocarbons C -C through line 17, a fraction boiling in the gasoline range through line 18 and gas-oil through line 19.

The distillation residue is conveyed through line 20 and after passage through a second oven sent .to a second distillation column 22 operated under reduced pressure.

There is thus obtained a heavy gas-oil from line 23 and different oil fractions from lines 24, 25 and 26.

The products issuing from the second distillation column have a content of sulphur impuritieslower than 0.1 percent by weight and generally lower than 0.02 percent. i

Nitrogen amounts to less than 30 ppm by weight (parts per million of parts of oil).

The Conradson carbon amounts to less than 0.10 percent by weight and generally less than 0.05 percent.

It has been mentioned that the hydrotreatment to which the charge is subjected in the reactor 4 is equivalent to a hydrogenation combined with a cracking; this operation is accompanied with a formation of hydrogen sulphide H S, ammonia NH; and very light hydrocarbons, more particularly methane.

These three compounds and more particularly the former two flow essentially from the separator 8 as a mixture with unconsumed hydrogen (a much smaller portion is discharged through duct 12). It is important, when it is desired to recycle the unconsumed hydrogen, to remove completely the than 60 percent (by volume), percentage of C CO being at most 2.5 percent. The catalyst may for example contain:

from 2 to 10 percent by weight of cobalt or nickel (expressed as C00 or NiO);

from 10 to 30 percent by weight of molybdenum or tungsten (expressed as M00 or W0 from 5 to 40 percent by weight of silica and from 22 to 83 percent by weight of alumina (with a preferred ratio by weight of Al O to SiO in the range of from 1.5 to 6).

The outflow from the hydrotreatment reactor is directed, through line 6, to a first gas-liquid separator or flash 8, also called high pressure separator (HP).

The temperature of the mixture flowing through duct 6 has been previously lowered by passage of the mixture through the cooler 7.

In the separator 8 there is recovered, at one end, a liquid phase conveyed through line 9 to a second separator l0, called'low pressure separator (LP) and, at the other end, a gaseous mixture rich of hydrogen and flowing through duct 11.

A portion of said gaseous stream is removed, the other being recycled, through line 5, to the hydrotreatment reactor 4. The gas removed from the system may be used for other purposes, for example as combustible gas.

The operation of the separator 10 is similar to that of the first separator except that the pressure is considerably lower (a few kg/cm instead of several tens or even hundreds of kg/cm There is obtained, at the outlet of the second separator, a gaseous mixture removed through line 12 and a liquid phase ammonia and partially the hydrogen sultide and the very light hydrocarbons. This is achieved by known means.

"Various particularly interesting solutions are described in the French patent l 582 758.

According to a known process, the vacuum distillation residue containing at least 50 percent by weight of constituents boiling above 525C, withdrawn through duct 27, mayeither be considered as a base oil and used as such, or may be recycled into the reactor 4.

In the latter case, a mere recycling has many inconveniences: as a matter of fact, the recycled residue being formed of molecules of high molecular weights relatively unaffected by the hydrotreatment, its recycling to the reactor 4 results in a decrease of the catalyst activity and accordingly requires more severe operating conditions for its conversion to lighter products.

The distillate withdrawn from lines 24, 25 and 26 must have relatively constant characteristics. The recycling of the distillation residue through line 27 into the reactor 4, having after a long time the detrimental effect of modifying the catalyst activity, results accordingly in a much more rapid modification of the characteristics of the desired products; in particular it has been observed during the cycle, that the aromatic content suffers substantial changes in the recycled residue and, to a lower degree, in the distillates withdrawn from lines 24, 25 and 26.

It has now been discovered that by passing, during a second step, the distillation residue withdrawn from line 27 through a second reactor containing a catalyst identical to or different from that of the first reactor, it is possible to convert partially or entirely the distillation residue to lighter products while avoiding the above-mentioned drawbacks. This distillation residue, which has been subjected to a substantial conversion during its passage in reactor 4, has a very high paraffinic character and a small content of impurities:

Nitrogen s 100 ppm by weight Sulphur s 500 ppm by weight Conradson carbon s 0.1 by weight Asphaltenes s 0.05 by weight According to the process of the invention, this distillation residue is withdrawn through line 27, heated in the oven 28, optionally after being admixed with fresh hydrogen conveyed through line 27, then sent through line 29 to a second hydrotreatment reactor 30, optionally fed with a gas rich of molecular hydrogen intro duced through line 34.

The operating conditions of reactor 30 are preferably as follows:

L.H.S.V. of from 0.1 to 2 liters of liquid charge per liter of catalyst and per hour.

Ratio of the flow rate of pure gaseous hydrogen to the flowrate of liquid charge from 500 to 5,000 liters per liter.

Preferably, the operating conditions in the second reactor 30 are not so severe as those in the first reactor 4, i.e. the L.H.S.V. is higher (1.2 to 2 times higher than the L.H.S.V. in reactor 4), and the temperature lower (for example from 10 to 100C lower than the temperature in reactor 4); the hydrogen partial pressures being the same in reactors 4 and 30.

Reactor 30 comprises, as well as reactor 4, at least one catalyst bed. The catalyst may, for example, contain:

from 2 to 10 percent by weight of cobalt or nickel (expressed as CoO or NiO) from 10 to 30 percent by weight of molybdenum or tungsten (expressed as M00 or W0 from 25 to percent by weight of silica and from 2 to 75 percent by weight of alumina (with a preferred ratio by weight of A1 0 to SiO in the range of from 0.1 to 1).

Alumina may be amorphous or crystallized; in the latter case, suitably exchanged zeolites may be incorporated thereto (zeolites with a sodium, calcium or lanthanum base by way of example). The zeolitic portion amounts for example to 3 to 15 percent by weight of the total catalyst.

Other catalysts for use in the first or second stage of the process may contain at least one noble metal from group VIII, for example platinum, and at least one carrier such as alumina-silica, chlorinated alumina or fluorinated alumina. Molybdenum or tungsten may also be used, with or without nickel or cobalt, on a halogenated alumina carrier. Other equivalent catalysts, known in the art, may also be used.

The effluent from the hydrotreatment reactor is conveyed through lines 31 and 33 to the first gas-liquid separator 8.

The temperature of the mixture flowing through duct 6 has been previously lowered by passage of the mixture through the cooler 32.

The recycling according to the invention, by passage of the distillation residue to a second reactor, avoids the above mentioned inconveniences. Moreover, this treatment gives a very high flexibility to the process of manufacturing lubricating oils. Particularly, it provides for the possibility, at the desired V.I. level, of maximizing the yields of oily distillates withdrawn from lines 24, 25 and 26 and of changing the distribution of these fractions according to the demand on the markets.

The accompanying drawing is only a simplified diagram of a unit operated according to the invention. Of course, there can be obtained, according to the nature of the charge and the severity of the treatment, a higher or lower number of oil fractions ranging from the Spindle-oil type to the heavy distillate type (three fractions are shown, by way of example, on the FIG- URE). This is also true for the first distillation column 16, particularly with respect to the different fractions obtained (in addition to the residue circulating through line 20).

The different oil fractions obtained from the second distillation are generally subjected to a dewaxing treatment not illustrated on the FIGURE (for example by a mixture methylethylketone-toluene) before being used as base oils to which various additives are generally incorporated.

As hereabove indicated, the FIGURE is only a simplified diagram on which the pumps, compressors, and the like are not shown. The reactor, the distillation columns, the coolerare apparatuses of the type commonly used for this kind of operation.

EXAMPLE Manufacture of Bases for Multigrade Oils EXAMPLE 1 The charge is a deasphalted residue having the following composition:

i 20 =0.928 S =2.58 by weight =800 ppm by weight =35.7 cst =7 distilled at 500C l5 distilled at 525C 85 having a boiling point higher than 525C Conradson carbon Viscosity at 98.9C Distillation ASTMl I60 The charge, at the outlet of the first reactor (line 6), has the following composition: by weight) H,S+NH, 2.84 C|+C2 0.42 C -t-C 1.62 C t-C, 2.60 Gasoline 80- l 50C 6.20 Gas-oil 38.42 Oily base 50.00

This base oil, distilled under reduced pressure, gives the following fractions: 100 Neutral: 25% i.e. 12.5% by weight of the initial charge 180 Neutral: 30% i.e. l5 by weight of the initial charge 400 Neutral: 25 i.e. 12.5 by weight of the initial charge The distillation is discontinued when the temperature (corrected at the atmospheric pressure) reaches 525C. The remaining distillation residue thus amounts to 20 percent of the base oil, i.e. 10 percent by weight of the initial charge.

The catalyst used in the first reactor had the following composition:

Composition:

Al O 56 (by weight) SiO, 20 M00; 16 MO 8 Specific surface 250 m /g Total porous volume 55 cc/ g Microporous volume 33 cc/lOO g O.lp.) Macroporous volume 22 cc/IOO g According to the process of the invention the distillation residue is conveyed to a second reactor. The reaction conditions are as follows:

PH, =l40 kg/cm L.H.S.V. =1 liter per liter of catalyst and per hour RH: =l ,000 liters per liter of liquid charge The catalyst of the second reactor has the following composition:

Composition:

A1 0 2! (by weight) SiO, 55 W0 20 MO 4 Specific surface 250 m /g Total porous volume 55 cc/IOO g The product obtained at the outlet of the second reactor contains 40 percent of light products, which will be later withdrawn from lines l7, l8 and 19 and 60 percent of a base oil. These 60 percent of base oil correspond to 6 percent of the initial charge, since the distillation residue amounted to 10 percent of the initial charge. These 6 are distributed as follows: 100 Neutral: 2.4 by weight of the initial charge Neutral: 1.8 by weight of the initial charge 400 Neutral: 1.8 by weight of the initial charge There is no residue.

As a total, there are thus obtained from lines 24, 25 and 26:

lOO Neutral l80 Neutral 400 Neutral The characteristics of the total base oil (mixture of the products from the first and the second steps) is as follows: viscosity at 98.9C 8 cst, V.I. 125.

The viscosity index (V.I.) has been determined according to the method defined by the Standard ASTM Conradson Carbon s 0.02

It has been possible to operate this process over a period of at least l2 months without any catalyst regeneration.

By way of comparison, there has been used a single reactor into which the unconverted residue is recycled. In these conditions, it was necessary to regenerate the catalyst after 2 or 3 months. Moreover, in the latter case, the composition of the base oil is variable during time, because of the adjustments of the catalyst temperature, required for compensating its deactivation.

In this example, all the distillation residue has been converted to light products in the second reactor. But it must be stated that, according to the charge and the required distribution of the oils, the conversion in the second reactor may be either complete or partial. In the latter case, the distillation residue obtained from the initial charge and the distillation residue obtained from the residue treated in the second reactor are withdrawn through line 27 and conveyed together to the second reactor.

EXAMPLE 2 Example 1 is repeated except that the following catalysts are used:

First reactor:

The total yield by weight is as follows:

100 Ncutral I80 Neutral 400 Neutral s s s What we claim as this invention is:

l. A process for manufacturing a lubricating oil comprising passing a deasphalted distillation residue of crude oil containing at least 85 percent by weight of constituents boiling above 500 C. and at least 75 percent by weight of constituents boiling above 525 C. with hydrogen through a first catalytic zone containing a hydrogenating element and a cracking carrier consisting essentially of, by weight, 2 10 percent cobalt or nickel, l 30 percent molybdenum or tungsten, 40 percent silica and 22 83 percent alumina, with a weight ratio of A1 0 to SiO of 1.5 6, at a temperature of from 330 to 450 C. and a hydrogen partial pressure of from 80 to 240 kglcm at such a flow rate that the hydrocarbons boiling below 525 C. in the resulting product amount to to 95 percent of the initial weight of such hydrocarbons, separating relatively light products boiling below 525 C. and recovering a first lubricating oil fraction of high V.l., passing at least a portion of relatively heavy products boiling above 525 C. together with hydrogen through a second catalytic zone containing a hydrogenating element and a cracking carrier consisting essentially of, by weight, 2 10% cobalt or nickel, 10 30 percent molybdenum or tungsten, 25 percent silica and 2 75 percent alumina, with a ratio by weight of A1 0 to SiO of 0.1 1, at a temperature of from 330 to 450 C. and a hydrogen partial pressure of from to 240 kg/cm at such a flow rate that at least the major part of said relatively heavy products of said first zone is converted to products boiling below 525C, and distilling the resulting products to separate a second lubricating oil fraction.

2. A process according to claim 1, wherein the operating conditions in the first catalytic zone are such that the weight of the hydrocarbons boiling below 525C, in the resulting product, amounts to from to 92 percent of the initial weight of such hydrocarbons.

3. A process according to claim 1, wherein the deasphalted residue has an initial boiling point higher than 300C, and contains at least percent by weight constituents having a boiling point higher than 500C.

4. A process according to claim 3, wherein the deasphalted residue has a viscosity at 989C of from 5 to centistokes.

5. A process according to claim 4, wherein the deasphalted residue has a viscosity of from 5 to 50 centistokes at 989 C., a viscosity index of from 0 to 100, a maximum content of asphaltenes of 0.3 percent by weight, a nitrogen content lower than 0.3 percent by weight and a maximum Conradson carbon of 5 percent by weight.

6. A process according to claim 1, wherein the flow rate of liquid charge is from 0.1 to 2 liters per liter of catalyst per hour and the hydrogen flow rate is from 500 to 5,000 liters per liter of liquid charge in each of the two catalytic zones.

7. A process according to claim 1, further comprising blending the first and second lubricating oil fractions, so as to obtain a blend of high V.l. lubricating oils.

8. A process according to claim 1 wherein the flow rate of the liquid charge in the second catalytic zone, expressed in liters per liter of catalyst per hour, is from 1.2 to 2 times that of the first catalytic zone.

9. A process according to claim 1, wherein the temperature in the second catalytic zone is 10 to 100C lower than the temperature in the first catalyticzone. 

2. A process according to claim 1, wherein the operating conditions in the first catalytic zone are such that the weight of the hydrocarbons boiling below 525*C, in the resulting product, amounts to from 85 to 92 percent of the initial weight of such hydrocarbons.
 3. A process according to claim 1, wherein the deasphalted residue has an initial boiling point higher than 300*C, and contains at least 90 percent by weight constituents having a boiling point higher than 500*C.
 4. A process according to claim 3, wherein the deasphalted residue has a viscosity at 98.9*C of from 5 to 100 centistokes.
 5. A process according to claim 4, wherein the deasphalted residue has a viscosity of from 5 to 50 centistokes at 98.9* C., a viscosity index of from 0 to 100, a maximum content of asphaltenes of 0.3 percent by weight, a nitrogen content lower than 0.3 percent by weight and a maximum Conradson carbon of 5 percent by weight.
 6. A process according to claim 1, wherein the flow rate of liquid charge is from 0.1 to 2 liters per liter of catalyst per hour and the hydrogen flow rate is from 500 to 5,000 liters per liter of liquid charge in each of the two catalytic zones.
 7. A process according to claim 1, further comprising blending the first and second lubricating oil fractions, so as to obtain a blend of high V.I. lubricating oils.
 8. A process according to claim 1 wherein the flow rate of the liquid charge in the second catalytic zone, expressed in liters per liter of catalyst per hour, is from 1.2 to 2 times that of the first catalytic zone.
 9. A process according to claim 1, wherein the temperature in the second catalytic zone is 10* to 100*C lower than the temperature in the first catalytic zone. 